Game plan for assembling aluminum gantry

[WoodSnarfer]

I'm about ready to send my gantry plans off to a waterjet service, to have my parts cut out of 0.472" 6061 or 6063.

Since I have very limited metalworking gear at home (basically, a drill press) I was thinking that it may be a good idea to draw in screw through-holes in my gantry parts, and let the waterjet cut the holes for me.

For example, if I'm joining two plates at a 90 degree angle, let the waterjet cut the face holes in the first plate, then when I receive the parts I will drill the end (receiving) holes and tap them.

I figure that I can clamp the pieces together and the through-holes can act as a drill guide for me to drill the end holes with my hand drill. I can even stack a couple of pieces of the 0.472 together, to make an even better (deeper) drill guide. I realize that I may have to widen the holes that the waterjet cut for me, after I'm done drilling the end holes (since I'll need to tap the end holes). I should be able to widen them on my drill press.

Does this make sense?

Thanks,
Chris

[edo]

I would definitely recommend having them 'cut' pilot holes for you. I know it would be a lot more accurate than I'd be able to measure and drill, even with a drill press. I'd be concerned with how accurate you'll be able to drill holes in the mating plate. You'll need some sort of a jig to hold the pieces together while you drill, I don't think you'll get good enough accuracy with just clamps.

Once you decide what size screws to use, have the holes 'jetted' to the size needed for the tap. Use these holes as a guide with the same size drill bit to drill into the mating piece. Then drill out the holes in the end pieces to the right clearance size for the screws. Here's a good link to recommended hole sizes for taps and clearance for different size screws. There's probably a standard for screw sizes, but I don't know what it is. I wouldn't go any bigger than 1/4" into .472" material.

[FrankM]

Originally Posted by WoodSnarfer I'm about ready to send my gantry plans off to a waterjet service, to have my parts cut out of 0.472" 6061 or 6063. Since I have very limited metalworking gear at home (basically, a drill press) I was thinking that it may be a good idea to draw in screw through-holes in my gantry parts, and let the waterjet cut the holes for me. For example, if I'm joining two plates at a 90 degree angle, let the waterjet cut the face holes in the first plate, then when I receive the parts I will drill the end (receiving) holes and tap them. I figure that I can clamp the pieces together and the through-holes can act as a drill guide for me to drill the end holes with my hand drill. I can even stack a couple of pieces of the 0.472 together, to make an even better (deeper) drill guide. I realize that I may have to widen the holes that the waterjet cut for me, after I'm done drilling the end holes (since I'll need to tap the end holes). I should be able to widen them on my drill press. Does this make sense? Thanks, Chris

Have them cut the holes but don't use them as guides to drill your tap size
get a set of transfer punches .